16:9 Aspect Ratio Calculator
Enter any one dimension and this calculator works out the other two so your image, video, or screen stays perfectly 16:9. Choose your solve mode (width, height, or diagonal), flip between landscape and portrait, and see the result as a labeled rectangle. A reference table of every standard 16:9 resolution from 360p to 8K is included below.
What is the 16:9 aspect ratio?
The 16:9 aspect ratio means a frame is 16 units wide for every 9 units tall. Expressed as a decimal, that is 16 / 9 = 1.7778, so any resolution where width / height equals 1.7778 is 16:9, whether that is 1280 x 720, 1920 x 1080, or 3840 x 2160. The ratio was adopted by SMPTE and the ITU in the 1980s and 1990s as the international standard for HDTV, and today it dominates televisions, computer monitors, laptop screens, online video platforms, and streaming services. YouTube, Netflix, and most gaming titles all use 16:9 as their primary display canvas.
How to use this calculator
Select what you want to solve for: height from a known width (the most common use case), width from a known height, the diagonal of a rectangle whose width you know, or width and height from a known diagonal. Then choose the orientation (landscape for standard widescreen, portrait for vertical video or mobile content) and the unit (pixels, inches, centimetres, millimetres, or points). Enter the known dimension and all three output values update instantly. The "show your work" panel walks through every arithmetic step so you can reproduce the result by hand or in a spreadsheet.
The formulas explained
For a 16:9 landscape frame: height = width / (16/9) = width x 0.5625, and width = height x (16/9) = height x 1.7778. For the diagonal, apply the Pythagorean theorem: diagonal = sqrt(width^2 + height^2). To work backward from a diagonal, width = diagonal / sqrt(1 + (9/16)^2) = diagonal x 0.8719 (rounded), and height = width x (9/16). In portrait (9:16) mode, the ratio flips: width = height x (9/16) and height = width x (16/9). These relationships hold in any consistent unit, pixels, inches, centimetres, or millimetres.
Common 16:9 resolutions and their names
720p (1280 x 720) was the original HD broadcast standard. 1080p (1920 x 1080) became the dominant consumer standard during the 2010s and remains the most common resolution for streaming and gaming. 1440p or QHD (2560 x 1440) is standard on high-end monitors. 4K UHD (3840 x 2160) has become common for premium televisions and is increasingly used on computer monitors and in professional video production. 8K (7680 x 4320) is the emerging standard for broadcast production and large-format displays. All of these are exact multiples of the 16:9 ratio, which is why upscaling and downscaling between them preserves the frame without cropping.
Standard 16:9 resolutions
| Width (px) | Height (px) | Name / Standard |
|---|---|---|
| 256 | 144 | Quarter nHD |
| 640 | 360 | nHD (360p) |
| 854 | 480 | FWVGA (480p) |
| 960 | 540 | qHD (540p) |
| 1280 | 720 | HD / 720p |
| 1600 | 900 | HD+ / 900p |
| 1920 | 1080 | Full HD / 1080p |
| 2560 | 1440 | QHD / 1440p (2K) |
| 3200 | 1800 | QHD+ / 1800p |
| 3840 | 2160 | 4K UHD |
| 5120 | 2880 | 5K Retina |
| 7680 | 4320 | 8K UHD |
Common landscape resolutions used in television, streaming, monitors, and gaming.
Frequently asked questions
How do I calculate the height for a 16:9 video?
Multiply the width by 9 and divide by 16, or equivalently multiply by 0.5625. For example, a width of 1920 gives a height of 1920 x 9 / 16 = 1080. You can also use the calculator above: set "Solve for" to "Height (given width)", enter 1920, and read off 1080.
What is 16:9 as a decimal?
16 divided by 9 is 1.7778 (repeating). This is the width-to-height ratio: for every 1.7778 units of width there is exactly 1 unit of height in a 16:9 frame.
Is 1920 x 1080 exactly 16:9?
Yes. 1920 / 1080 = 1.7778, which equals 16/9 exactly. You can verify it by dividing both numbers by their greatest common divisor (120): 1920/120 = 16 and 1080/120 = 9.
How do I find the diagonal of a 1920 x 1080 screen?
Use the Pythagorean theorem: diagonal = sqrt(1920^2 + 1080^2) = sqrt(3686400 + 1166400) = sqrt(4852800) = 2202.9 pixels. If you know the physical pixel density (PPI), you can convert that to inches.
What is the difference between 16:9 and 9:16?
16:9 is landscape (wider than tall), used for televisions, monitors, and most online video. 9:16 is portrait (taller than wide), used for vertical social video on TikTok, Instagram Reels, and YouTube Shorts. The two ratios are mathematical inverses: 16/9 = 1.7778 and 9/16 = 0.5625.
Why is 16:9 the standard aspect ratio for HD video?
The Society of Motion Picture and Television Engineers (SMPTE) and the ITU selected 16:9 in the 1980s as a compromise between the 4:3 ratio used in traditional television and the wider ratios (such as 2.35:1) used in cinema. It covers the widest film formats reasonably well while fitting analog and early digital broadcast constraints. By 2009, virtually all new televisions worldwide had switched to 16:9 screens.